Metal fabric coating process and apparatus



F. c. BRIGHTLY, JR 2,933,410

COATING PROCESS AND APPARATUS 2 Sheets-Sheet. 1

April 19, 1960 METAL FABRIC Filed May 3, 1957 April 19, 1960 F. c. BRIGHTLY, JR 2,933,410 7 METAL FABRIC comma PROCESS AND APPARATUS Filed May 3, 1957 2 Sheets-Sheet. 2

EF Z

described in two commercial thicknesses.

Unite States METALFABRIC COATING PROCESS AND APPARATUS Frederick C. Brightly, Jr., Oak Par Ill. Application May 3 1957, Serial No. 656,981 14 Claims. (Cl. 117-51) This invention relates generally to coating fabric in roll" form, and more specifically to an improved method and apparatus for galvanizing chain-link fence fabric after the weaving thereof.

Although the principles of the present invention may be included in various coating processes or apparatus for same, a particularly useful application is made in galvanizing complete rolls of iron or steel chain-link fence fabric, such as is commonly utilized as fencing along modern highways.

Various objects have'been galvanized both by the hot dip method, and by electroplating. The electroplaters have had an economic advantage over the users of the hotdip method whereby they have been able to set a selling price for their product which, while profitable to them, would be unprofitable if adopted by the users of the hot dip process. This is particularly true when buyers specify that the galvanizing coating must not have holes or clear spots in the coating" such as would be present if the coating were applied to the fabric while the fabric was in roll form. This fact is of great concern to the users of the hot-dip method, particularly when the mar ket caused by the national highway building program would be available to them if their price were both profitable and competitive.

Zinc coating is applied to fence fabric of the type In one class, a minimtun of 1.20 ounces of zinc are applied per square foot of tin-coated wire surface (AS-TM spec. A392-55T, class 1). In a better classof galvanizing, such as is used for highway fence, the coating is 2.0 ounces of zinc' per square foot of uncoated wire" surface. The hot-dip method usually relies on the time at which the fabric is exposed to the molten zinc to determine the weight which is deposited on the fabric. Therefore, the 1.20 ounces may be applied at a given rate of production determined by the characteristics of the galvanizing machine eg. for No. 9 gage wire, a typical. machine exposes the fabric to molten zinc at a temperature of 875 F. for 24 seconds. In order to produce the thicker grade of. coating. on the same ma chine, it becomes necessary to slow down the machine so that the fabric is exposed for a longer period of time to the molten zinc, the time being 70- seconds in the above example. While the same machine maybe slowed down to produce the higher grade of material, a smaller volume of production results, which smaller volume is compelled to carry the same economic overhead that a larger volume of production can carry where the coating is thinner. Accordingly, the cost rises rapidly, and has been found: to be above the market price established by users of the electroplating process.

The present: invention. contemplates the utilization of a cradle within the zinc kettle whereby one or more rolls of fabric maybe preheated and may be unrolled While immersed in zinc,. and thereafter be directed to a zinc 2,933,410 Patented Apr. 19, 1960 "ice done at a relatively high speed or short duration of immersion, so that the thickness may be controlled by the length of time in which the roll of fabric is immersed in molten zin'cbefore it is unreeled. Accordingly, by my invention; the galvanizing machine may be run atthe same high speed for the heavy grade of coating as may be used for running'the thinner grade of coating.

Accordingly, it is an object of the present invention to provide a method and means for applying galvaniz-' ing material to fabric using the hot-dip process.

It also is an object of this invention to modify the hot-dip galvanizing process so that it is economically competitive. 7

Another object of the present invention is the pro vision of a method and apparatus for efficiently applying a galvanizing coating to a fabric in roll form, without producing any minute spots where there-is no galvanizing, such spots being determined by points of contact between fence elements when'in roll form.

Yet another object of the instant invention is the provision of a process and apparatus for galvanizing wire fabric while it is in roll form, but without the creation of any welds in the resulting structure at the points of contact between elements of the fence fabric.

Many other advantages, features and additional objects of the present invention Will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way or illustrative example.

on the drawings:

Figure l is a side elevational view, partially in section and partially diagrammatic, of an apparatus for practicing the process of this invention;

Figure 2 is an end view of the Figure l; and

Figure 3 is a view taken along line III-III of Figure 2.

As shown on the drawings:

The principles of this invention are particularly useful when embodied in a galvanizing method and apparatus such as is illustrated by the attached drawings.

It is now a common practice in the art to pickle the rolls of a fabric as received in an 8% solution of sill furic acid, to rinse the rolls using hot water after the rolls have been removed from the pickling solution, and to apply a pre-fluxing solution to the" rolls consisting of zinc ammonium chloride. In the present invention, the rolls are subjected to this same preliminary treatment (not shown) or to an equivalent treatment preparatory to their being galvanized.

Referring to Figure 1, the apparatus includes generally a kettle 10 which extends normal to the plane of the drawing. A pair of walls of the kettle, such as 11 and 12, are exposed to heat such as coming from a furnace jacket 13. Supports, such as a pair of masonry supports 14 may be provided about the furnace jacket 13 for holding in the heat within the kettle 10 and for supporting a galvanizing. apparatus generally indicated by the numeral 15 thereabove.

The apparatus 15 includes a frame 16 in which is journalled a group of three shafts 17, 18 and 19, each carrying a sprocket wheel 2i) rotatable therewith and exposed to the room air above the kettle it}. The wheels 20 have sprocket teeth sized to engage the openings in the fabric F. The frame 16 also supports a drive motor 21 which is connected as by a chain drive 22 to a power shaft 23. The power shaft 23 is connected to each of the shafts =17-19 for driving them in a clockwise direction, as viewed. This connection may comprise any convenient means, such as bevel gears on the respective structure shown in shafts. The apparatus preferably also includes a clutch and brake 24 underthe control of a lever 25 whereby rotation of the sprocket wheel 20 or the stoppagethere'of may-be simultaneously effected. The apparatus 15 also includes intermediate the-shafts 18 and 1-9, a bath 26 in which water or other suitable material may be placed for washing and cooling the finished product. An idler 27 operates in the bath and is journalled in the frame 16 to insure that the fabric will pass through the bath 26. Zinc which has a melting point of about 418 C., is placed into the kettle 10 up to the level indicated by the numeral 30 and is maintained in a molten condition at a conventional galvanizing temperature by the furnace jacket 13 or any other source of heat. A downwardly depending dam 31 is carried by the frame 16 which darn extends into the molten zinc. The surface 30 of the molten zinc on to cause the various shafts to turn in such a. direction as to unreel or unwind the roll R as best shown in Figure 1. During the unreeling and primarily during the soaking, zinc is deposited on the fabric of the roll. As the fabric is unwound, a certain amount of flexing of the links occurs whereby the various points of contact become exposed to the molten zinc. Assuming that inadequate fluxing had occurred at such points, such points become exposed to the flux 32 as the webF is upwardly drawn into room air by rotation of the shaft 17. The zinc will lose heat to the room air and will solidify at a temperature of about 418 C., and the flexing caused by the directing of the web F about the sprocket wheel one side of the darn is covered with an appropriate flux such as sal-ammoniac 32, while on the other side of the dam 31, .the surface 30 carries a quantity of charcoal 33 which is used as a wipe for the fabric. The charcoal 33 may be further restricted such as by a pair of channels 34 if desired. If desired, the dam 31 may be provided with an anti friction device 35 at its lower end. A pair of brackets 40, here shown as generally having a J-shape, form a cradle generally indicated at 41 for receiving a roll R of fabric F. The longer legs of the J brackets extend upwardly and out of the kettle 10, across the support 14, and around a channel iron 42. A plurality of rods 43 extend from the one bracket 40 to the other to space such brackets from each other and to rigidify the cradle 41.

; The kettle 10 extends in a direction perpendicular to the plane of the drawing beyond the mechanism 15, and may extend in either or both directions from the apparatus 15. Since the channels 34 completely surround the web F, it is not necessary for the dam 31 to extend 20 of the shaft 17 causes the welds produced by, the zinc to break. Thereafter, the web F is again exposed to the flux 32 and is again directed downwardly through the molten zinc, about the anti-friction means 35, and upwardly through the charcoal wipe 33. It is to be understood that the length of web which is below the surface 30 of the zinc will in part determine the capacity of the machine for a given operating speed. Upon leaving the charcoal wipe 33, the web is exposed to the air which again effects the solidification of the zinc and the web F is again flexed by the sprocket wheel 20 carried by the shaft 18 to again break any zinc welds which may be present. Since it is contemplated to operate this machine at a relatively high speed, it is preferable tocool the finished web, washing it at'the bath 26 through which the web F is pulled by motion of the shaft 19 and its sprocket wheel 20. The web F is thereafter directed to a conventional re-rolling unit 47.

It may be expected that the coating deposited on the fabric while the roll R was in the soaking station or to the ends of the kettle 10. However, it is to be understood that the furnace and masonry support would extend substantially coextensively with the kettle 10.

Referring to Figure 2, it can be seen that additional brackets 40 are provided and that the rods 43 extend lengthwise of the kettle 10 for a distance suflicient to support one or more rolls of wire within the cradle 41 endwise of the roll R at an unwinding station 45 which is in line with the apparatus 15. Thus the cradle 41 extends longitudinally of the kettle to form additional cradles or stations adjacent to each other. Thus a station or cradle 46 comprises a soaking station for rolls of wire not yet processed through the apparatus 15.

Referring to Figure 3, preferably the brackets 40 in the stations other than the unreeling station 45, extend transversely across the kettle 10 to the far side, the flux 32 extending across the entire surface of the zinc at the soaking station 46.

Rolls of fabric R may be handled by an overhead conveyor and be lowered at a point indicated by the numeral 50 in Figure 3, through the flux 32 into the molten zinc and onto the brackets 40 and the rods 43 on which they may be rolled in a slightly downwardly direction to the soaking position as shown. As best shown in Figure 2, the roll R may then be skidded laterally within the cradle such as by means of a hand held hook to the unreeling station 45, in preparation for unreeling. Ordinarily the end of the roll is secured to adjacent links or stakes as by auxiliary wire, which wire encircles the roll during handling. When the roll is about to be inserted into the soaking portion of the kettle, one end of the wire may be disconnected and unwound from the roll R and reconnected so that the wire forms a loop, the ends of which are connected to the leading edge of the web of fabric F. When the roll arrives in the unreeling station, the loop may be cut at its center and the two out ends of wire connected to the trailing edge of the preceding roll of fabric. When the rolls are so connected, the lever 25 may be actuated cradle, may be uneven and may have points where there is little or no coating. By running the web F through the kettle 10, around the anti-friction means 35, the coating initially deposited is smoothed out and any low spots in the coating are filled in to thereby provide a uniform product of good workmanship.

It is to be understood that while this invention has particular utility with respect to chain-link type of fence fabric, and to galvanizing a fence, such references herein are by way of illustration and not by way of limitation. Thus the process andapparatus herein disclosed,-may be used with other coating materials and on other articles.

Although various minor modifications might be suggested by those versed in the art, it should be understood that I wish to embody ,within the; scope of the patent warrantedhereOn all such embodiments as reasonably and properly come within the scope of my contribution to the art.

I claim as my invention:

1. A method of controlling the thickness of galvanizing on metal fabric comprising immersing the fabric in molten zinc, allowing said fabric to remain stationary therein for a predetermined variable period of time, and thereafter, maving the fabric through the molten zinc at any fixed high rate for all desired nominal thicknesses of galvanizing.

2. A method of hot-dip coating rolls of open wire fabric comprising flowing molten coating material for a predetermined period of time through the roll to deposit a relatively large proportion of molten coating material onto the fabric throughout the roll while the fabric is in roll form and stationary; after said period of time has elapsed, unreeling the coated roll below the surface of the molten material, and thereafter, rapidly passing the unrolled fabric through the molten material to smoothen and even out the finish of the coating.

3. A method of continuously galvanizing a plurality of rolls of metal fabric comprising the stepsof immersing a roll of fabric in molten zinc to preheat it for a predetermined period of time, thereafter unwinding the as it is unwound through the molten zinc, and re-rolling the galvanized fabric after the zinc has solidified.

4. A method of galvanizing a roll of metal fabric comprising the steps of passing the room-temperature roll through a heated flux and into molten zinc as a roll, unwinding the roll after a predetermined period of such immersion has elapsed, moving the heated fabric from the molten zinc through the flux to prepare points which touched each other in roll-form for galvanizing, flexing thezinc-coated fabric in room air to break the resulting Zinc welds, thereafter moving the unwound fabric through the flux and into the molten zinc and flexing it during said moving, drawing the fabric out of the molten zinc, and after the zinc has solidified, re-rolling the fabric.

5. A method of galvanizing a roll of metal fabric comprising the steps of immersing the roll of fabric in molten zinc for a predetermined period of time, thereafter unwinding the roll while so immersed, moving the unwound fabric through the molten zinc, and re-rolling the fabric.

6.. A method of galvanizing a roll of metal fabric comprising the steps of immersing the cntire roll of fabric in molten zinc until it has reached a temperature above 418 C., thereafter unwinding the immersed fabric, immediately moving the unwound fabric through the molten zinc, and re-rolling the fabric.

7. A method of galvanizing a roll of metal fabric comprising the steps of immersing the roll of fabric in molten zinc for a predetermined period of time, thereafter unwinding the roll while so immersed, moving the unwound fabric from the molten zinc through a flux, thereafter passing the unwound fabric through molten zinc, and re-rolling the fabric.

8. A method of galvanizing a roll of metal fabric comprising the steps of passing the roll of fabric through a flux, immersing the roll in molten zinc for a predetermined period of time, thereafter unwinding the roll below the surface of the molten zinc, passing the unwound fabric through a flux, thereafter passing the unwound fabric through molten zinc and flexing it during said passing, cooling the fabric to a temperature below 418 C., and re-rolling the fabric.

9. Apparatus for galvanizing a roll of fence metal fabric comprising in combination, a heated kettle for holding molten zinc; a cradle within said kettle for supporting only the entire roll below the surface of the zinc; an unwinding station adjacent to said cradle for receiving said roll from the cradle; and means for unwinding the roll at said station and moving the fabric through the molten zinc.

10. Apparatus for galvanizing a plurality of rolls of metal fabric comprising in combination, a heated kettle for holding molten zinc; a cradle for supporting at least two rolls adjacent to each other below the surface of the molten zinc, said cradle having an unreeling station and a soaking station; and means for unwinding the roll in said unreeling station and moving the fabric web through the molten zinc, whereby the roll. in said soaking station is preheated by molten zinc for subsequent transfer to said unreeling station.

11. Apparatus for galvanizing a plurality of rolls of metal fabric comprising in combination, a heated kettle for holding molten zinc; a soaking station within said kettle for depositing a zinc coating on the fabric only while in roll form; a second station adjacent to said soaking station for receiving said roll therefrom; and means operative at said second station for smoothening and evening out the zinc coating on the fabric while the fabric is in web form.

12. Apparatus for galvanizing a plurality of rolls of metal fabric comprising in combination, a heated kettle for holding molten zinc; a soaking station within said kettle for depositing a zinc coating on the fabric only while in roll form; a second station adjacent to said soaking station for receiving said roll therefrom; and means acting on the fabric at said second station for unwinding the coated roll below the surface of the molten zinc, said means directing the fabric about the molten zinc in said kettle to even out and smooth the coating.

13. Apparatus for galvanizing a plurality of rolls of metal fabric comprising in combination, a heated kettle for holding molten zinc; a soaking station within said kettle for depositing a zinc coating on the fabric only while in roll form; a second station adjacent to said soaking station for receiving said roll therefrom; means acting on the fabric at said second station for unwinding the coated roll below the surface of the molten zinc, said means directing the fabric about the molten zinc in said kettle to even out and smooth the coating; means for cooling the galvanized fabric before it is re-rolled, and means for receiving the galvanized fabric from the kettle and for guiding the fabric to said cooling means.

14. Apparatus for galvanizing a roll of metal fabric comprising in combination: means for holding a quantity of molten zinc; a cradle disposed only to support the roll entirely beneath the surface of the molten zinc; an unwinding station adjacent to said cradle for receiving the roll from said cradle and for supporting the roll entirely beneath the surface of the molten zinc; and means for unwinding the roll at said station and moving the fabric through the molten zinc.

References Cited in the file of this patent UNITED STATES PATENTS 10,349 Waring et al. July 3, 1883 2,318,320 McFadden May 4, 1943 2,401,956 Overbeke June 11, 1946 2,435,766 Baley Feb. 10, 1948 2,797,173 Keller June 25, 1957 

2. A METHOD OF HOT-DIP COATING ROLLS OF OPEN WIRE FARBRIC COMPRISING FLOWING MOLTEN COATING MATERIAL FOR A PREDETERMINED PERIOD OF TIME THROUGH THE ROLL TO DEPOSIT A RELATIVELY LARGE PROPORTION OF MOLTEN COATING MATERIAL ONTO THE FABRIC THROUGHOUT THE ROLL WHILE THE FABRIC IS IN ROLL FORM AND STATIONARY, AFTER SAID PERIOD OF TIME HAS ELAPSED, UNREELING THE COATED ROLL BELOW THE SURFACE OF THE MOLTEN MATERIAL, AND THEREAFTER, RAPIDLY PASSING THE UNROLLED FABRIC THROUGH THE MOLTEN MATERIAL TO SMOOTHEN AND EVEN OUT THE FINISH OF THE COATING. 